Apparatus and method for enhanced dehumidification

ABSTRACT

A method and apparatus for enhancing performance of a dehumidifier that is operating in a substantially closed air environment facilitates air-to-air heat exchange between a first air stream derived from the closed air environment and a second air stream derived from a source other than the closed air environment, the second air stream being cooler than the first air stream.

BACKGROUND OF THE INVENTION

The invention relates to dehumidifiers, and more particularly toimproved performance and efficiency.

Dehumidifiers are known in the prior art. A compressor delivers hotcompressed refrigerant gas. A condenser receives the refrigerant gas andcondenses same into hot refrigerant liquid. An expansion device receivesthe refrigerant liquid from the condenser and expands same to drop thetemperature and pressure of the liquid. An evaporator receives the coolliquid refrigerant from the expansion device and evaporates same to coldgas refrigerant, which is returned to the compressor to complete therefrigeration cycle. Air flow is directed across the evaporator to coolthe air below the dew point such that water vapor in the air iscondensed to liquid to dehumidify the air. The dehumidified air is thendirected across the condenser to warm the air.

The present invention arose during continuing development effortsdirected toward improved performance and efficiency in a dehumidifier.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 shows a dehumidifier known in the prior art.

FIG. 2 is a schematic illustration of a dehumidification system known inthe prior art.

FIG. 3 is a perspective view showing a dehumidifier, including aportable cabinet, known in the prior art.

FIG. 4 shows the dehumidifier of FIG. 3 partially broken away, showingprior art.

FIG. 5 is a side view of the dehumidifier of FIG. 4, showing prior art.

FIG. 6 is a perspective view of a dehumidifier and apparatus forenhancing the performance of the dehumidifier, in accordance with thepresent invention.

FIG. 7 is a side view, broken away, of the arrangement shown in FIG. 6.

FIG. 8 is a perspective view, broken away, of apparatus for enhancingperformance of a dehumidifier.

FIGS. 9 a and 9 b are partial views showing attachment points forcoupling the apparatus for enhancing performance of a dehumidifier to adehumidifier.

FIGS. 10 a and 10 b are partial views of further attachment points forcoupling an apparatus for enhancing performance of a dehumidifier to adehumidifier.

FIG. 11 is a schematic illustration of an arrangement in accordance withthe invention.

DETAILED DESCRIPTION OF THE INVENTION Prior Art

FIG. 1 shows a dehumidifier 10 known in the prior art. A compressor 12delivers compressed hot gas refrigerant. A condenser 14 receives the hotgas refrigerant and condenses same to hot liquid refrigerant, and givesup heat to the air flow therethrough. An expansion device 16 receivesthe hot liquid refrigerant and expands same to a liquid and gasrefrigerant mixture of reduced temperature and pressure. Expansiondevice 16 is typically a flow restrictor, capillary tube, or otherpressure reducer. An evaporator 18 receives the cool liquid and gasrefrigerant mixture and evaporates the liquid portion to cool gasrefrigerant, and absorbs heat from the air flow therethrough. Therefrigerant is circulated from compressor 12 to condenser 14 toexpansion device 16 to evaporator 18 and back to compressor 12 in arefrigeration cycle. Air flow, typically driven by a fan (not shown), isdirected by a duct or housing 19 along a path through evaporator 18 andcondenser 14. As the air flows through evaporator 18 from point 20 topoint 22, the temperature of the air drops below the dew point such thatwater vapor in the air is condensed to liquid to dehumidify the air. Theair is heated as it flows through condenser 14 from point 22 to point24, and the warmed and dehumidified air is discharged to the desiredspace, such as a basement, or other interior space of a house orbuilding.

FIG. 2 further schematically illustrates the dehumidification of systemof FIG. 1 and uses like reference numerals where appropriate tofacilitate understanding. It is known to provide a heat exchanger 26 a,26 b for pre-cooling the air upstream of evaporator 18 and thenre-heating the air downstream of the evaporator.

FIGS. 3-5 show a dehumidifier 28 including a portable cabinet 30,compressor 12 in the cabinet for delivering hot compressed refrigerant,condenser coil 14 in the cabinet and receiving refrigerant fromcompressor 12 and condensing same, capillary tube expansion device 16 inthe cabinet and receiving refrigerant from condenser coil 14 andexpanding same, and evaporator coil 18 in the cabinet and receivingrefrigerant from expansion device 16 and evaporating same, anddelivering the refrigerant to compressor 12. The refrigerant iscirculated from compressor 12 to condenser coil 14 to expansion device16 to evaporator coil 18 and back to compressor 12 in a refrigerationcycle, as is known.

Cabinet 30 has an air flow path 32 therethrough, including a firstsegment 34, FIG. 5, passing ambient air to evaporator coil 18, a secondsegment 36 passing air from evaporator coil 18 to condenser coil 14, anda third segment 38 discharging air from condenser coil 14. The first,second and third segments, 34, 36 and 38, are in series from upstream todownstream, respectively. Heat exchanger 26 has first and second heatexchange paths 26 a and 26 b therethrough in heat exchange relation, forexample provided by a plurality of layered corrugated sheets providingvertical air flow channels therethrough at 26 a in heat exchangerelation with a plurality of interdigitated corrugated layered sheetsproviding horizontal flow channels therethrough at 26 b, providing anair-to-air cross flow heat exchanger as is known. Heat exchanger path 26a provides pre-cooled ambient air from which moisture is removed byevaporator coil 18. Pre-cooling incoming air improves grain depression,capacity (pints per day), and efficiency (pints per kilowatt hour). Theremoved moisture is collected at collection pan 40 having drainageoutlet 42. The air is re-heated at heat exchanger flow path 26 b, andthe warm dry air is supplied to condenser coil 14 as pulled therethroughby squirrel cage blower 44 which discharges the dehumidified air atoutlet 46 as shown as arrow 47. Portable cabinet 30 may be mounted onwheels such as 48 and have a handle such as 50 for maneuvering thecabinet and rolling it along a floor such as 52.

The dehumidifier shown in FIGS. 3-5 is often utilized to dry floodedsurfaces and/or structures in a closed-air environment such as abasement, room, or other substantially enclosed area. In use, thedehumidifier takes in and removes moisture from air in the environmentand thereafter emits warm, dry air back into the environment. The warm,dry air raises the temperature of the environment and advantageouslyspeeds evaporation rates from the flooded surfaces, structures and/orother areas. However, increasing the air temperature of the environmentsimultaneously causes a decrease in performance of the dehumidifier interms of its water removal rate. Therefore, according to knownarrangements, there is a tradeoff between raising the air temperature toachieve rapid evaporation rates and lowering the air temperature toachieve effective dehumidification rates.

Present Invention

FIGS. 6-11 illustrate the concepts of the present invention and use likereference numerals from above when appropriate to facilitateunderstanding.

In FIGS. 6-11, an apparatus or amplifier 60 is provided for enhancingperformance of a dehumidifier 28 that is operating in a substantiallyclosed-air environment, such as a basement, room or other substantiallyenclosed area. As discussed further below, the apparatus 60 improves thegrain depression, capacity, and efficiency of the dehumidifier 28.

In the illustrated embodiment, apparatus 60 includes a cabinet 62containing an air-to-air heat exchanger 64. The cabinet 62 is formedfrom stainless steel, however it is recognized that any structurallyrigid metal or other material could be used. The cabinet 62 has a firstinlet 70 adapted to receive the aforementioned first air stream 32 fromthe closed air environment and a first outlet 74 discharging the firstair stream 32 to the intake 108 on the dehumidifier 28 fordehumidification according to the above-described process. Intake airthus flows vertically through the apparatus 60 as shown in FIGS. 6 and7. A second inlet 76 is adapted to receive a second air stream 78originating from a cool air source other than the surroundingenvironment. The second air stream 78 must be cooler than the air fromthe closed-air environment and can derive from an air conditioningsystem or unaffected outside air. A second outlet 80 is provided fordischarging the second air stream 78 to a location other than theclosed-air environment. The second air stream 78 thus flows through theapparatus 60 horizontally, as shown in FIGS. 6 and 7. In the preferredarrangement, the second inlet 76 and second outlet 80 are ducted andtherefore the second air stream 78 is separated from the closed-airenvironment.

In the arrangement shown, the heat exchanger 64 has first and secondheat exchange paths 64 a and 64 b therethrough in heat exchangerelation, for example provided by a plurality of layered corrugatedsheets providing vertical air flow channels therethrough at 64 a in heatexchange relation with a plurality of interdigitated corrugated layeredsheets providing horizontal flow channels therethrough at 64 b,providing an air-to-air cross flow heat exchanger 64. A motorizedimpeller 82 is arranged in the cabinet 62 to force the second air stream78 horizontally along the second path 64 b of the heat exchanger 64. Ina preferred arrangement, the impeller 82 is controlled by a thermostaticcontroller, which automatically turns the impeller off when processedair reaches a predetermined temperature. Thermostatic controllers areknown in the art and may include a bimetallic switch with a sensingelement in the primary air stream. The controller is set to turn theimpeller on when the process air temperature increases to 80 degreesFahrenheit, and off when the process air cools to 70 degrees Fahrenheit.Alternatively, the impeller may be controlled manually and thus be setto run continuously, if desired. In the arrangement shown, a powerswitch is located on the back of the cabinet to allow for manual controland/or control by the thermostatic controller.

The cabinet 62 is designed to detachably mount to the intake 108 of thedehumidifier 28. It is recognized that various different means formechanical connection may be employed to achieve this objective. In thearrangement shown, the bottom 87 of the cabinet 62 is sized to nest inthe top 88 of the dehumidifier 28 and the top 89 of the cabinet 62 isarranged to receive the lid 84 and filter 86 of the dehumidifier 28.More specifically, prior to attachment of the cabinet 62 to the top 88of the dehumidifier 28, the lid 84 and filter 86 are removed from thetop 88. Slots 90 on the front lower end 92 of the cabinet 62 are sizedand positioned to receive spring clips 94 located in the top 88 of thedehumidifier 28. Tabs 96 extending downward from the rear lower end 98of the cabinet 62 have an aperture 100 sized and shaped to receive aknob 102 extending from the outer rear side 104 of the top 88 of thedehumidifier 28. As shown in FIGS. 9A and 9B, the front lower end 92 ofthe cabinet 62 is inserted at an angle into the top 88 of thedehumidifier 28. Slots 90 on the cabinet 62 are guided to receive tabs94 of the dehumidifier 28. As shown in FIGS. 10A and 10B, the rear lowerend 98 of the cabinet 62 is lowered and slid forward towards the frontupper end 106 of the dehumidifier 28 until knobs 102 are engaged by theapertures 100 of tabs 96. The lid 84 and filter 86 of the dehumidifier28 are then placed on the top 89 of the cabinet 62. When it is desiredto remove the cabinet 62 from the dehumidifier 28, the above process isrepeated in reverse.

The top 89 of the cabinet 62 is also sized slightly bigger than thebottom 87 of the cabinet 62, to allow for stacking and transporting ofmultiple cabinets 62. In a preferred arrangement, the cabinet 62 alsoincludes handles 61 to simplify transport and use.

When the cabinet 62 is attached to the dehumidifier 28, the first outlet74 aligns with the inlet 108 on the dehumidifier 28. The blower 44 onthe dehumidifier 28 draws air flow vertically through the amplifier 60as shown at 32. The second inlet 76 is pneumatically connected to theunaffected cool air source, such as an air conditioned system or anunaffected or ambient outside air source. The second air stream 78 has alower temperature than the first air stream 32, which derives from thesurrounding environment. As shown in FIG. 11, apparatus 60 is arrangedto cool the input air stream 32 before it is drawn into the dehumidifier28, thus preventing the dehumidifier 28 from losing performance, even ifthe air in the closed-air environment has a high temperature. Apparatus60 cools the air by exchanging heat with the second, relatively coolerair stream 78.

In applications where the temperature of the secondary air stream 78 issignificantly below the dew point of the primary air stream 32,condensation may occur inside the heat exchanger 64. A drip pan 99underneath the heat exchanger 64, along with the mounting bracket 97secured in the dehumidifier 28, direct condensate towards the front ofthe dehumidifier 28 and downward into the dehumidifier's drip pan 40 forremoval.

According to the invention, an apparatus, system and method are providedthat increase the efficiency of a dehumidifier. The invention increaseswater removal rates up to at least 100% and increases the graindepression up to 33% for faster drying of more materials. The inventionpreserves dehumidifier moisture removal rate that would otherwise belost when surrounding air temperatures increase. The depictedarrangement is unique in that it couples directly to the intake of thedehumidifier 28 and provides an easy set-up having only two ductconnections. Close-coupling to the dehumidifier 28 minimizes the imposedpressure drop on the dehumidifier's blower system. The drip pan 99advantageously directs water into the dehumidifier 28 in casecondensation occurs inside the apparatus 60. Also, the invention allowsfor use of additional heat generating equipment in the drying space,such as fans, additional dehumidifiers, etc. Use of such additionalequipment further increases drying rates.

It should be understood that the drawings and specification are to beconsidered an exemplification of the principles of the invention, whichis more particularly defined in the appended claims. For example,although the depicted arrangement is for attachment to a particulardehumidifier, the invention is applicable for use with a variety ofdehumidifiers such as standard refrigerant-based or dessicantdehumidifiers. The concepts of the invention are also applicable for usein a system that that operates outside of an environment to bedehumidified, wherein the air streams are ducted to and from theenvironment.

1. An apparatus for enhancing performance of a dehumidifier that isoperating in a substantially closed air environment, the apparatuscomprising: a cabinet adapted to removably attach to the dehumidifier,the cabinet having a first inlet receiving a first air stream from theclosed air environment; a second inlet receiving a second air streamfrom a source other than the closed air environment, the second airstream being cooler than the first air stream; a first outletdischarging the first air stream to the dehumidifier; a second outletdischarging the second air stream; and an air-to-air heat exchanger inthe cabinet, the air-to-air heat exchanger facilitating heat exchangebetween the first and second air flows to thereby cool the first airflow prior to discharge of the first air flow to the dehumidifier andwarm the second air flow prior to discharge of the second air flow. 2.The apparatus of claim 1, comprising a fan for driving the second airstream through the cabinet.
 3. The apparatus of claim 2, comprisingmeans for thermostatically controlling the fan.
 4. The apparatus ofclaim 1, comprising means for removably attaching the cabinet to adehumidifier.
 5. The apparatus of claim 4, wherein the means forremovably attaching the cabinet to a dehumidifier comprise a slot on thecabinet.
 6. The apparatus of claim 4, wherein the means for removablyattaching the cabinet to a dehumidifier comprise a tab having anaperture.
 7. The apparatus of claim 1, wherein the secondary air streamis discharged to an area other than the substantially closed airenvironment.
 8. The apparatus of claim 1, comprising a baffle fordirecting condensate from the heat exchanger into the drip pan.
 9. Amethod for enhancing performance of a dehumidifier that is operating ina substantially closed air environment, the apparatus comprising:facilitating air-to-air heat exchange between a first air stream derivedfrom the closed air environment and a second air stream derived from asource other than the closed air environment, the second air streambeing cooler than the first air stream such that the first air stream iscooled; discharging the cooled, first air stream to an inlet on thedehumidifier for dehumidification.
 10. The method of claim 9, furthercomprising the step of dehumidifying the cooled first air stream anddischarging the dehumidified first air stream to the closed airenvironment.
 11. The method of claim 9, further comprising the step ofdischarging the second air stream to an area outside of the closed airenvironment.
 12. The method of claim 9, wherein the source is anair-conditioned source.
 13. An arrangement for dehumidification of asubstantially closed air environment, the system comprising: adehumidifier having an inlet for receiving moist air and an outlet fordischarging dehumidified air to the closed air environment; and anair-to-air heat exchanger having a first inlet receiving a first airstream from the closed air environment, a second inlet receiving asecond air stream from a source other than the closed air environment,the second air stream being cooler than the first air stream, a firstoutlet discharging the first air stream to the dehumidifier inlet, and asecond outlet discharging the second air stream.
 14. The arrangement ofclaim 13, comprising a cabinet housing the air-to-air heat exchanger,the cabinet adapted to removably attach to the dehumidifier.
 15. Thearrangement of claim 14, comprising an inlet cover adapted tointerchangeably fit on the dehumidifier when the cabinet is not attachedto the dehumidifier and on the cabinet when the cabinet is attached tothe dehumidifier.
 16. The arrangement of claim 15, wherein the inletcover comprises an air filter.
 17. The arrangement of claim 13,comprising a duct carrying the second air stream from the source to thesecond inlet.
 18. The arrangement of claim 13, comprising a ductcarrying the second air stream from the second outlet to an area otherthan the closed air environment.
 19. The arrangement of claim 13,comprising a fan for driving the secondary air stream through theair-to-air heat exchanger.
 20. The arrangement of claim 19, wherein thefan is thermostatically controlled.